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Is there any difference between the actual TBI throttle bodies from an 88-91 318 or an 89-92 360? So far I can tell that the injectors themselves are different, higher flowrate for the 360, but what about the throttle bodies? Is there any performance improvement that could be seen from putting a 360 TB and injectors on a 318 or would be putting 360 injectors in the 318 TB be the same?
 

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i believe they both have same diamter butterflies. i dont believe using 360 injectors is a good idea. im pretty sure idle quality will suffer. unless you had a reprogrammed compuer or some kinda controller to cut back pulse width on idle. remember 318 computer will still think it has "small" injectors. im pretty sure the holley projection cointroller ($200 through summit) would work. APC has some super tuner crap. soon im ordering a mega squirt kit just to build for fun. they got some new high speed processor out and revised code.
 
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Gentlemen, consider this. Engines run on air. Gas, is just a catalyst. Therefore, why would one have higher flow injectors, but the same size airflow butterflies? The 360 has larger "barrels." Mopar Performance sold the 360 TBI (with a template to enlarge the 318 intake to clear the larger butterflies) with performance-oriented computer and hi-flow muffler as a performance upgrade for that era 318. Swapping injectors will only muck up the works. These units aren't very friendly to tinkering unless you really know how to do it. You must have the 360 computer with the 360 TBI........unless you enjoy pain. Going with the 360 setup on a 318 opens up the headroom for some power-building as long as you don't go nuts.
 

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How crazy could you go with a 5.9 ENG rebuild if you wanted to keep the TBi setup??
 
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Not very. CompCams offers what it calls an OEM replacement cam that is friendly with the stock computer. It offers a bit more duration, and considerably more lift (.480). It runs within the stock rpm, but with the increased lift, requires better springs (901's). This will definitely fill in the upper rpm power. Other than relieving some choke points in the exhaust, not much else will be tolerated by the computer without mods, or swapping the whole setup out for a Holley aftermarket TBI unit.
 

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Thats what I figured. Guess I'll be going with an upgraded fuel injection or back to carb. I'm looking to do a high 300horse 360 rebuild...I've almost got to force myself to do it though........over 130,000 and she still runs like a champ!!! :)
Thanks for the info!
 

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There is the simple analog setup, but at least it's tunable to changes, and will support higher hp. There's also the Commander version for more sophisticated tuning, as well as running TBI or MPI. There's a great benefit, even with the older analog system.
 

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I can testify to the fact that running 360 injectors in a factory OEM 318 TB, (1990), along with a SBEC, (Computer for a W250, 3/4 ton truck), makes a hell of a difference in performance. Given the right add ons to work with the extra gas, advance and fuel delivery curves, quite a bit of performance can be gained.

I just got back from Thailand and had some time to kill, (cause sleeping isn't on the agenda yet do to the time difference), so I installed the 360 computer today... LOL. Previously, I had fitted my '90 RC with an alum. intake, adapter plate for the TB, MP 300 hp service roller cam and lifter kit, (.443 lift), headers, 2 1/2" exhaust pipe flowing into Daytona turbo-z cats, K&N air cleaner and the noted 360 injectors, in an effort to fatten up the gas available to work with the cam and freerer flowing exhaust. Today I bolted the 360 omputer on and MAN WHAT A DIFFERENCE!!

I'm getting ready to drop a custom built, (To my specifications), 366, (.030 over 360) in to replace the 318. The 360 will develop 350 hp and 400+ lb/ft. of torque, all below 5200 rpm, and is emissions friendly. (.470 lift cam, 9.8:1 compression), swirl polished stainless 2.02 1.68 valves and the ports have been "cleaned up." Intake is the Edelbrock Performer, (just like I'm running now), and fuel is the standard 93-94 octane I always run with 11.5 deg advance.

I'm looking for a 360 TB as I heard the same thing, that they can be opened up in both the throats and the base pate to enhance flow, (CFM), capability. My adapter plate that currently matches the stock opening of the OEM 318 cast iron intake, can be modified / adjusted any way I want. Bigger is better as long as it doesn't exceed the base and throttle bores of the 360 TB.

I'm running 37 x 13.50 SSR's with 4.56 Trac loks front and rear. My 318 in the current configuration pulls my 24' big block Velocity on a custom 5" ship channel constructed 10K gvw trailer with relative ease. (Boat and trlr. approach 6,000 lbs), with 55 gals of gas on board.

I'm still looking for a good used '90 360 TB whether doated to the project or would like the opportunity to buy it for a fair price or perhaps trade for it.

Email me with any questions / suggestions or offers.

Thanks,

RWTD
 

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Too early to tell what kind of gas mileage I get with the new "360" computer powering the OEM 318 with 360 injectors. I jsut filled up last night with 93 oct gas, so I should have an answer in a couple of days. The improvement, overall is so dramatic, that knowing what I know now, I would have rebuilt the 318 and improved on the heads, (Either aftermarket or the larger 2.02's), that the new 360 came with and let it be. I know in the old configuration, with the old stock 318 computer, it would get right around 13-14 our on the highway. Problem was, with the factory convertor in the A518, it was almost impossible to build any low end torque inspite of the fact I advanced the cam as much as I could to improve the torque.

With just the installation of the 3/4 ton computer, the thing pulls likes gang busters from low end and the performance overall is noticably improved. It takes off from a dead stop like it never has. Throttle response has improved dramatically. I can pull hills in overdrive now, where I used have to downshift to drive to do it before. And this is with the right combination of parts, working together, through some well thought out experimentation.

I've been saying all along that these TB year(s) engines can be made to hustle if you're patient and are willing to develop a plan and work at it.

Just as soon as the weather breaks here in the Northeast, I'm going to manufacture the adapter plate I'm running on mine now that allows the use of an alum. intake, which is step #1 in the right direction.

Dave 8)
 

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So do you still have the factory converter, Dave, or did you switch it out? I've got a 90 RC I put a hughes cam in and am STILL trying to get it set up right (i think it's a vaccuum issue). I keep thinking i should but in one of those towing type torque converters cause I have to downshift to get up hills, also.

james
 

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James,

Depending on the specs on the cam that you installed, you could have a low vacum problem with the motor.

My cam is the Mopar Perf. 300 hp service roller cam and lifter set. Lift is .443 / .430, 274 / 264 with no centerline called out. This cam works extremely well. Builds lots of torque under 4800 rpm. I'm running a custom adapter plate that allows me to run the factory TB on an Edelbrock Performer intake that I gasket and port matched to the heads, headers, 2 1/2" dual cats and mufflers. the convertor is the stock factory convertor. It locks up tight at about 1750-1800 using the brake stall test methofd called out in the factory service manual. All the OEM emissions stuff is still in place, except the air injection which I eliminated when I installed the headers.

The 360 crate motor I have is built around 355 hp and 408 lb/ft torque, with a custom ground Crower roller. To help it get into the torque band and build maximum lowend torque, I custom ordered a fully rollerized ATI 2300 rpm stall speed convertor which should launch my 90 R/C like a funny car instead of a bulldozer, (like the stock convertor does now.) Towing won't be a problem, as the convertor is fully bearingized with Torrington bearings and the fins pitched so the convertor locks up tight at 2300 rpm. It's the same diameter as the stock convertor, so fluid volume remains the same, with the same cooling capacity.

Alot of the guys out there on RCC immediately assume there's going to be a problem with excess heat using this high of stall. Convertor technology has come a long way. I've been dealing with ATI for over 25 years. They know their stuff.

I'm also running a 12 pass 27k gvw supplemental cooler in series with 5 core radiator. Towing my 6000 lb boat and trailer on a 98 deg. day under heavy load, I've never seen the current A518 I'm running go over 170 degrees on the Autometer trans temp gauge I've got in the pan, and the trans has almost 145k on it. It does have the Transgo stage 2 shift kit in it though. (I'm going to leave that in the trans during the rebuild). Other than some improvements to oiling and possibly new and better pump gears to improve the operating pressure, I'm putting all Dodge clutches, bands and steels back in it.

A buddy of mine is going to rebuild my A518 O/D trans to A516 specs, (Add the extra clutches, etc), to handle the towing and limited wheeling I do, and add the 4.2:1 2nd gear apply lever and a new TCI +2 quart capacity cast aluminum pan. Given the added extra fluid of the cooler and the pan, heat should be the least of my worries.

These model years, (88-91), are the forgotten years, but I love the body style and I still have to meet emissions requirements here in MD. They're pretty tough. My current 318, even with the mods I listed, flys right through emission inspection.

The custom Crower cam in the new 360 is a 50 state C.A.R.B. approved cam. The magic is in the heads, 2.02 and 1.60 swirl polished and back cut valves with some mild port work done to improve flow.

Like I said, the single biggest improvement I made in the end, that took advantage of all of the other performance improvements I made to the 318, was the addition of the 360 3/4 ton truck computer and 360 injectors in my 318 TB.

Dave
 

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Wow, thanks Dave for your reply. I've got a hughes 9204 http://www.hughesengines.com/cams/la_hyd_roller.asp and bought it for the torque properties that they said it would produce without it messing up the computer. I think I finally got it working pretty close to where it should be, but i need to test drive it some more. I was expecting it to have more vacuum than the 18Hg that i'm getting right now, but it could be a small leak somewhere ???

It sounds like your engine is set up to make it's power a little higer up in the rpm range, maybe really getting going above 2000? When I started to research to build mine (I had no little to no knowledge of engines) I went with this cam, gapless rings, stock intake with the tbi, new springs on the heads, 3 angle grind, but no porting or polishing to keep the turbulence up at the lower RPM. That was also why i didn't mess with the TB, leaving it smaller for higher velocity. But now with what you've told me, i am very intrigued. Of course, my engine rarely sees anything over 2500 or 2800 RPM, and i usually just putt-putt around when wheeling between 1000 and 2000, and when crusing the highway, i keep it at about 1800 to 1900, so I don't know if that type of mod would be usefull to my driving style. If I could get more power with a 360 TB and computer, i might just try it. What kind of gas mileage difference have you noticed with the change?

I would like to beef up the tranny someday, thought. How much "beefier" is the A516? do you order an A516 rebuild kit and stuff everything in there? Thanks again Dave.

James
 
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What's this A516 biz? Did I miss something, or do you guys mean the A618, which is a heavy duty version of the A518?
 

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The A618 is the Cummins Turbo Diesel version of the A518. More and better clutches, along with a 3 disc lock-up convertor. The A518 I have, does not have the lock up convertor. From what I've learned, the performance improvement I've gotten from the 360, 3/4 ton truck computer is due to better fuel delivery and advance curve mapping to support towing and / or hauling heavy loads these trucks are capable of hauling due to their GVW rating, using the same 360..Gas mileage wasn't a principal concern when these computers were designed for the application. From what I can tell, my gas mileage is about the same, (Over 150 miles since I installed it), by the gauge. The performance gain, though, (ie; seat of the pants) feel is tons better. Taking off from a stop light, midrange and even top end has improved substantially. I'm not sure yet, but I would bet the rpm limiter is considerabally higher too. My old 318 computer computer started busting the motor up at about 5500 rpms. Haven't manually shifted it yet. When I do, I'll let you know what the top rpm is. As my 318 is presently built, it should be capable of 5800-6000 rpms with no problems.

Dave
 
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I know what the A618 is. I've seen so many references to the "A516" (five-sixteen), that I was beginning to think I'd missed something in the lineup.
 
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